Printing device



I. GURWICK PRINTING DEVICE Aug. 15; 1939.

Filed Jan. 2l, 1938 Patented Aug. 15, 1939 UNITED STATES PATENT .OFFICE PmN'rnvG DEVICE v Irving Gurwick, Mount Vernon, Ohio, asslgnor to Shellmar Products Company, Mount Vernon,

Ohio, a corporation of Delaware Application January 21, 193s, .serial No. 186,051

` claims. (011011-151) sion is made.

An additional object of the invention is to provide means for supplying a volatile solvent atmosphere for an intaglio printing cylinder between the doctor blade and the impression roll, so that the ink contained in the etched portions of the cylinder will remain in a iluid condition without -being deleteriously affected by the solvent atmosphere. y

Still another object of the invention is to provide a sheltered wick-like evaporator or solvent applicator between the doctor blade of an intaglio printing cylinder and the impression roll, the wick-like solvent applicator to be supplied with a liquid volatile solvent which evaporatesv reference to the accompanying drawing, in which Fig. 1 is an end view partly in section of a device for applyingsolvents in accordance with the present invention; and

Fig. 2 is a longitudinal sectional view taken along line 2-2 of Fig. 1.

In intaglio printing better results can be obtained'if the ink contained in the etched printing y cylinder is maintained in a iuid condition without y the web to be decorated. In accordance with the present invention there is provided an improved means whereby the printing cylinder is protected against solvent loss between the doctor blade and the impressionl roll by providing a solvent atmosphere which will maintain the ink on the printing cylinder fluid and will not cause the ink to become too fluid or to produce a blotched or pebbled eiect upon the printed web.

In the device shown in Figs. 1 and 2 of the drawing the numeral II) denotes anetched `intaglio printingcylinder ofconventional construction.' This cylinder rotates about4 shaft I I in a color bath denoted generally at I2. Within the color bath I2 is maintained a body of liquid ink of the usual type employed in intaglio presses.' Generally these inks containy a colored pigment and a body-imparting substance such asa gum or cellulose compound which is contained ina liquid volatile solvent of low boiling point. As the cylinder I0 rotates in the lcolor bath it picks up an overall coating of the ink both in its etched and unetched surfaces.

Mounted adjacent the cylinder I0 is a doctor` blade mechanism including an upright standard I3 upon which is mounted an adjustable sleeve I4. The sleeve I4 carries an adjustable doctor blade holding device I5, the latter being mounted to the sleeve I4 by an adjustable screw P6. To the end of the holder I5k adjacent the printing cyl- I1. 'I'his doctor blade and the solvent applicator holder I8 are secured to the holder I5 by means of the bolts I9. It will be understood .that the `inner end of the doctor blade I1 bears against the surface of the printing cylinder I0 and acts to remove excess ink from the cylinder except where the cylinder is etched. These blades are of conventional construction and need no further description.

Theholder I8 has rotatably mounted to it at its inner end 20 a semi-cylindrical shield 2| composed of a thin metal or similar gas-impervious cover. This hood or shield is shaped concentrically with the cylinder l0 and is spaced therefrom as shown in the drawing. At space points 22 and 23 the hood 2| is perforated and secured over these perforations is a communicating solvent supply line 24. Line 24, in turn, has'connected'to it a reservoir 25, the reservoir being adapted to contain a liquid supply of the solvent with which it is desired to maintain theA ink in a fresh condition. A suitable valve 26 acts to control the amount of the solvent added to the dev1ce.

Beneath the cover or hood 2I and adjacent the end thereof arel bearing members 21 and 28,

-these members acting to space the hood 2| from the printing cylinder and to provide a substantially gas-tightcompartment therebetween. The

bearing members are secured'to the under side of the hood and ride on the outer, unetched 4marginal portions of the printing cylinder. Between the members 2l and 28 there is provided ar fibrous pad 29. This padmay be felt or some `other corn-4 position which will absorb solvent coming through the lines 24 andprevent the solvent from dripping onto the printing cylinder in liquid condition,`

and is secured to the under side of the hood ZI. The pad also is spaced from the surface of the inder I0 is clamped a conventional doctor blade y.

printing cylinder to an extent suicient to pre vent contact of the pad with the etched portions of the cylinder. v

a greater content of high boiling solvent.

`terious effect upon the printing cylinder.

Valve 26 is regulated to supply the desired quantity of liquid solvent to line 24, and this solvent passes from line 24 through the openings 22 and 23 to the wick-like solvent applicator 29'. The solvent is distributed interiorly of the solvent applicator 29 by capillary attraction. From the under surface of the pad'29 the solvent is free to evaporate into the space between shield 2l and the printing cylinder. This causes the space to become saturated with the solvent. When this space becomes saturated with the vaporous solvent it will be seen that evaporation of the solvent contained in the ink of the etched portions of the printing cylinder will be retarded. This insures the ink reaching the printing cylinder in the same fresh condition in which it is applied to.

the cylinder. Ordinarily Where there is a substantial space between the doctor blade I1 and the impression roller there is a time interval during which the ink may evaporate to an undesirable extent between the doctor blade and the impression roller. This is prevented by the protective atmosphere of solvent supplied adjacent the printing cylinder by the evaporation applicator.

'I'he particular solvent to be used in the improved applicator may vary widely. In an intaglio ink the solvent generally consists of a mixture of different low boiling compounds such as toluol and the like, and these solvents may have different boiling points. A mixture of such solvents may be employed in the reservoir 25 or one of the solvents may be so utilized. By utilizing the lowest boiling of the solvents employed in the ink the atmosphere beneath the hood 2l will be saturated in this lower boiling solvent and when so saturated the content of this solvent in the ink on the cylinder will be maintained. The higherboiling solvents may evaporate to some extent but this evaporation is retarded by the presence of the saturated solvent atmosphere above the cylinder. By employing small quantities of the higher boiling solvent in the reservoir 25 along with the lower boiling solvent even this evaporation may be maintained at a minimum.

In one embodiment of .the invention there is provided in the reservoir 25 a solvent of a substantially high boiling point. The atmosphere adjacent the printing cylinder and beneath the hood 2l between the doctor blade and the impression roller thenwill contain this relatively high boiling solvent. .The relatively high boiling solvent may penetrate to some extent the outer surface of the ink contained in the etched' portions of the printing cylinder. As it is this outer surface ofthe ink which is contacted with the web to be printed it will be seen that the layer of ink after application to the printed surface will be richer in low boiling solvents on the outside and adjacent the printed web there ywill be The low boiling solvents will quickly escape with travel of the web from the unit to produce a crust of dried ink on the outer surface of the web. More time will be allowed for the higher boiling solvent adjacent the web to dry and it will be found that this type of printing is particularly desirable in many cases.

Wherev the solvent applicator involves the evaporation of the solvent from a fibrous surface of the nature described herein there is no dele- A wicklike pad will allow the vapors to Asaturate the atmosphere between the hood 2| and the printing -cylinder at a temperature substantially the same as the temperature of the printing cylinder, so that evaporation of the ink from the printed matter in the etched portions of the cylinder is minimized and the solvent from the pad 29 does not condense upon the printingcylinder. It is important that the solvent not be present in the form of globules of unvaporized solvent even though these globules may be quite small as in the case of a very fine spray. Such a spray contains very small particles of liquid solvent which impart to the printed matter on the cylinder I0 a pebbled appearance which is very undesirable'.

The particular type of solvent applicator pad 29 may be varied quitev considerably. Also, the space between the hood 2l or the pad 29 and the printing cylinder likewise is subject to wide variation. vIn some cases it will not be found necesh sary to employ the bearing members 21 and 28, since the escape of solvent from the ends of the hood 2| is replaced by additional solvent from the reservoir 25 to maintain the space between the hood and the printing cylinder saturated with the solvent.

The various modiilcations which may be made in the invention as described herein for purposes of illustration and explanation are intended to be included in the appended claims.

I claim:

l. In an intaglio printing unit, an etched printing cylinder, means for supplying said printing cylinder with an intaglio ink containing a volatile solvent, a doctor blade for said printing cylinder adapted to remove excess ink therefrom, an impression roller spaced from said doctor blade, a hood extending between said doctor blade and said impression roller, a ilbrous` pad attached to the under side of said hood, and a reservoir for solvents communicating through said hood and with said pad.

2. lIn an intaglio printing unit, an etched printing cylinder, means for supplying to said etched printing cylindera liquid ink containing a volatile solvent, a doctor blade for removing excess ink from the printing cylinder, an impression roller spaced from the doctor blade, and a solvent pad adjacent said printing cylinder between the doctor blade and impression roll.

3. In an intaglio printing unit, an etched printing cylinder, means for supplying to said etched printing cylinder a liquid ink containing a volatile solvent, a doctor blade for removing excess ink from the printing cylinder, an impression roll spaced from the doctor blade, and an absorbent solvent pad adjacent said printing cylinder -between the doctor blade and the impression roll, said pad including means for supplying liquid solvent thereto.

4. In a printing unit, a printing cylinder. means for supplying to said printing cylinder a liquid ink having a volatile solvent, an absorbent porous material positionedl adjacent a portion of said printing cylinder, and means for supplying to said material a solvent of like nature to the solvent in said ink.

5. In a printing u'nit, a printing cylinder, means for supplying-to said printing cylinder a mobile ink having av volatile solvent, and an absorbent porous material positioned adjacent a portion of said printing Vcylinder spaced from said means for supplying ink thereto, Asaid material having a volatile solvent constituting a vehicle for said ink therein andproviding an atmosphere .of said solvent adjacent said cylinder.

IRVING GURWICK. 

